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Troubleshooting Question

How to add another VLAN to a Cisco Router

Last Modified: 2020-12-21
Hi -

I have three stacked C3750E core L3 switches, that connect to some stacked L2 cisco switches  WS-C2960S-48FPS-L. I am trying to add a new VLAN with the following network subnet/IP- - NOW Below are my interface information and I noticed that I have a VLAN120 which is our active wired VLAN. You will see below that this VLAN has which I believe is the default gateway for I am confused here, and believe maybe the is already present? I connected my laptop to the interface assigned to VLAN120 on the L2 switch and I received a - Address. I am trying to create a network subnet for another network for

On my L2 and L3 switches currently

interface Vlan120
 description Wired Clients
 ip address
 ip helper-address
 no ip proxy-arp

Interface              IP-Address      OK? Method Status                Protocol
Vlan1                  unassigned      YES NVRAM  administratively down down
Vlan101          YES NVRAM  up                    up
Vlan107          YES NVRAM  up                    up
Vlan108          YES NVRAM  up                    up
Vlan109          YES NVRAM  up                    up
Vlan110         YES NVRAM  up                    up
Vlan111         YES NVRAM  up                    up
Vlan113         YES NVRAM  up                    up
Vlan114         YES NVRAM  up                    up
Vlan120         YES manual up                    up
Vlan124         YES NVRAM  up                    up
Vlan131         YES NVRAM  up                    up
FastEthernet0          unassigned      YES NVRAM  administratively down down
GigabitEthernet1/0/1   unassigned      YES unset  up                    up
GigabitEthernet1/0/2   unassigned      YES unset  down                  down
GigabitEthernet1/0/3   unassigned      YES unset  down                  down
GigabitEthernet1/0/4   unassigned      YES unset  down                  down
GigabitEthernet1/0/5   unassigned      YES unset  down                  down
GigabitEthernet1/0/6   unassigned      YES unset  down                  down
GigabitEthernet1/0/7   unassigned      YES unset  down                  down
GigabitEthernet1/0/8   unassigned      YES unset  down                  down
GigabitEthernet1/0/9   unassigned      YES unset  down                  down
GigabitEthernet1/0/10  unassigned      YES unset  down                  down
GigabitEthernet1/0/11  unassigned      YES unset  down                  down
GigabitEthernet1/0/12  unassigned      YES unset  down                  down
GigabitEthernet1/0/13  unassigned      YES unset  down                  down
GigabitEthernet1/0/14  unassigned      YES unset  down                  down
GigabitEthernet1/0/15  unassigned      YES unset  down                  down
GigabitEthernet1/0/16  unassigned      YES unset  down                  down
GigabitEthernet1/0/17  unassigned      YES unset  up                    up
GigabitEthernet1/0/18  unassigned      YES unset  up                    up
GigabitEthernet1/0/19  unassigned      YES unset  up                    up
GigabitEthernet1/0/20  unassigned      YES unset  up                    up
GigabitEthernet1/0/21  unassigned      YES unset  up                    up
GigabitEthernet1/0/22  unassigned      YES unset  up                    up
GigabitEthernet1/0/23  unassigned      YES unset  up                    up
GigabitEthernet1/0/24  unassigned      YES unset  up                    up
GigabitEthernet1/1/1   unassigned      YES unset  up                    up
GigabitEthernet1/1/2   unassigned      YES unset  up                    up
GigabitEthernet1/1/3   unassigned      YES unset  up                    up
GigabitEthernet1/1/4   unassigned      YES unset  down                  down
Te1/1/1                unassigned      YES unset  down                  down
Te1/1/2                unassigned      YES unset  down                  down
GigabitEthernet2/0/1   unassigned      YES unset  down                  down
GigabitEthernet2/0/2   unassigned      YES unset  down                  down
GigabitEthernet2/0/3   unassigned      YES unset  down                  down
GigabitEthernet2/0/4   unassigned      YES unset  down                  down
GigabitEthernet2/0/5   unassigned      YES unset  down                  down
GigabitEthernet2/0/6   unassigned      YES unset  down                  down
GigabitEthernet2/0/7   unassigned      YES unset  down                  down
GigabitEthernet2/0/8   unassigned      YES unset  down                  down
GigabitEthernet2/0/9   unassigned      YES unset  down                  down
GigabitEthernet2/0/10  unassigned      YES unset  down                  down
GigabitEthernet2/0/11  unassigned      YES unset  down                  down
GigabitEthernet2/0/12  unassigned      YES unset  down                  down
GigabitEthernet2/0/13  unassigned      YES unset  down                  down
GigabitEthernet2/0/14  unassigned      YES unset  down                  down
GigabitEthernet2/0/15  unassigned      YES unset  down                  down
GigabitEthernet2/0/16  unassigned      YES unset  down                  down
GigabitEthernet2/0/17  unassigned      YES unset  down                  down
GigabitEthernet2/0/18  unassigned      YES unset  up                    up
GigabitEthernet2/0/19  unassigned      YES unset  up                    up
GigabitEthernet2/0/20  unassigned      YES unset  up                    up
GigabitEthernet2/0/21  unassigned      YES unset  up                    up
GigabitEthernet2/0/22  unassigned      YES unset  up                    up
GigabitEthernet2/0/23  unassigned      YES unset  up                    up
GigabitEthernet2/0/24  unassigned      YES unset  up                    up
GigabitEthernet2/1/1   unassigned      YES unset  up                    up
GigabitEthernet2/1/2   unassigned      YES unset  up                    up
GigabitEthernet2/1/3   unassigned      YES unset  down                  down
GigabitEthernet2/1/4   unassigned      YES unset  down                  down
Te2/1/1                unassigned      YES unset  down                  down
Te2/1/2                unassigned      YES unset  down                  down
GigabitEthernet3/0/1   unassigned      YES unset  up                    up
GigabitEthernet3/0/2   unassigned      YES unset  up                    up
GigabitEthernet3/0/3   unassigned      YES unset  up                    up
GigabitEthernet3/0/4   unassigned      YES unset  up                    up
GigabitEthernet3/0/5   unassigned      YES unset  up                    up
GigabitEthernet3/0/6   unassigned      YES unset  up                    up
GigabitEthernet3/0/7   unassigned      YES unset  up                    up
GigabitEthernet3/0/8   unassigned      YES unset  down                  down
GigabitEthernet3/0/9   unassigned      YES unset  down                  down
GigabitEthernet3/0/10  unassigned      YES unset  down                  down
GigabitEthernet3/0/11  unassigned      YES unset  down                  down
GigabitEthernet3/0/12  unassigned      YES unset  down                  down
GigabitEthernet3/1/1   unassigned      YES unset  down                  down
GigabitEthernet3/1/2   unassigned      YES unset  down                  down
GigabitEthernet3/1/3   unassigned      YES unset  down                  down
GigabitEthernet3/1/4   unassigned      YES unset  down                  down
Te3/1/1                unassigned      YES unset  down                  down
Te3/1/2                unassigned      YES unset  down                  down
Port-channel1          unassigned      YES unset  up                    up
Port-channel2          unassigned      YES unset  up                    up
Port-channel3          unassigned      YES unset  up                    up
Port-channel4          unassigned      YES unset  up                    up
Port-channel5          unassigned      YES unset  up                    up
Port-channel6          unassigned      YES unset  up                    up
Port-channel7          unassigned      YES unset  up                    up

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